1. Field of the Invention
This invention relates generally to a device for detecting occlusion in a fluid line, and more particularly relates to detection of occlusion in a fluid line upstream or downstream of a peristaltic type pump used for infusion of intravenous solutions to a patient.
2. Description of Related Art
Various devices have been used for infusing intravenous fluids to a patient. In order to gain more control over the rate of fluid flow than is generally available with gravity feed IV administration sets, various types of pumps and controllers have been utilized. A peristaltic type of pump has been found to be advantageous in allowing the pumping of intravenous fluid through conventional, flexible fluid lines without fluid contact. It has been found that the operation of peristaltic pumps also allows for a wide variety of control and sensing of patency and fluid flow conditions. Important data concerning flow status can be gathered by monitoring fluid pressure changes within the intravenous fluid line.
The incorporation of a pressure sensing strain gauge assembly in a peristaltic pump in order to monitor dimensional changes in the outer diameter of an intravenous tube as an indication of fluid pressure changes in the tube in known from U.S. Pat. No. 4,690,673. In the construction of such a pressure sensing assembly, the strain gauge is attached to a strain beam which is part of an assembly mounted on a fixed mounting block to press with a generally constant displacement of the fluid line.
It would be desirable to provide an apparatus for monitoring occlusion in a fluid line upstream or downstream of a peristaltic pump mechanism, or otherwise detecting fluid pressure changes in the fluid line for detecting changes in the rate of flow due to partial closure of the line, leaks in the line, or other such problems with a pressure sensor which presses against the line with a certain degree of displacement of the fluid line only during a limited portion of the duty cycle of the pump. Such a moving pressure sensor can avoid interfering with the fluid flow during the portion of the duty cycle when the pressure sensor is not pressing against the fluid line, and would allow for periodic calibration of the pressure sensor as well. Coordination of the movement of the pressure sensor with cam follower fingers of a peristaltic pump would be desirable in order to avoid interfering with the operation of the pump, while enhancing the accuracy of pressure measurements obtained. The present invention addresses these needs.